2. Definition
ASPIRATION is defined as the inhalation of oropharyngeal or gastric
contents into the larynx and lower respiratory tract.
The nature of the aspirated material, volume of the aspirated material, and
state of the host defenses are three important determinants of the extent and
severity of aspiration pneumonia.
Aspiration can occur at any time during the perioperative period.
3. Classification of aspiration
Aspiration pneumonitis is defined as acute lung injury after the inhalation
of regurgitated gastric contents.
Aspiration pneumonitis (Mendelson’s syndrome) is a chemical injury
caused by the inhalation of sterile gastric contents.
This condition involves lung tissue damage as a result of aspiration of non-
infective but very acidic gastric fluid .
4. Continued…
The pH value of less than 2.5 as a threshold for chemical pneumonitis and
the critical volume for severe pneumonitis is estimated at 0.8 mL/kg
Most common causes are drug overdose, seizures, a massive
cerebrovascular accident, or the use of anesthesia.
5. Continued…
Aspiration pneumonia develops after the inhalation of colonized
oropharyngeal material.
Any condition that increases the volume or bacterial burden of
oropharyngeal secretions in a person with impaired defense mechanisms
may lead to aspiration pneumonia.
Exogenous lipoid pneumonia (ELP) is a rare form of pneumonia
caused by inhalation or aspiration of a fatty substance. ELP has been
reported with inhalation or ingestion of petroleum jelly, mineral oils, “nasal
drops,” and even intravenous injection of olive oil.
6. Mechanisms for Protection of Reflux and Aspiration in the
Awake Patient
Lower esophageal sphincter tone (LES): is the primary barrier to gastro-esophageal reflux
Gastro-esophageal angle
Upper esophageal sphincter
Air way reflexes like:
Sneezing
Apnea
Swallowing
Laryngeal closure
Coughing
7. Risk factors for regurgitation and pulmonary
aspiration under general anesthesia
Obesity
Depressed level of consciousness
History of gastritis/ulcer
Bowel obstruction
Pregnancy – greater than 12 weeks gestation
Pain/stress
Emergency surgery
ASA IV-V
9. Signs of Pulmonary Aspiration
Signs usually occur within 2 hours of the event
Bronchospasm
A drop in oxygen saturation of greater than 10% on room air
A chest radiograph usually revealing atelectasis or an infiltrate
Adult respiratory distress syndrome (ARDS)
Hypoxia
Increased inspiratory pressure
Cyanosis
Tachycardia
Abnormal auscultation
11. Prevention
Pharmacologic agents
to decrease Gastric volume (either by decreasing production or by
increasing emptying),
Increase gastric pH, or
Increase LES tone
Metoclopramide
Facilitates gastric emptying by causing gastric peristalsis and relaxation
at the pylorus.
It also increases LES tone
Contraindications: bowl obstruction, Parkinson disease
12. Cimetidine or ranitidine
Are competitive H2-blockers that will decrease basal gastric acid secretions
Increase gastric PH.
Sodium citrate is a non-particulate antacid that will increase gastric pH.
13. Continued…
Omeprazole,Rabrazole,Lansoprazole are proton pump inhibitors that block
H+-K+-adenosine triphosphates' activity at the secretory surface of the
parietal cells in the stomach. These drugs decrease the volume and increase
the pH of gastric secretions
Glycopyrrolate, an anticholinergic, will increase gastric pH by inhibiting
vagal mediated gastric acid production. Atropine, however, is ineffective.
15. Case
• A 23 years old male patient comes to DRH with compliant of two episode of
vomiting, severe abdominal pain of 6 hours duration and diagnosis as acute
appendicitis and scheduled for appendectomy. The anesthetist perform rapid
assessment and found the following.
History no previous anesthesia and surgery exposure. He has history of burn 5
years later at the neck area chest as well recently eat food.
PE slight limitation of neck movement 2 fingerS admit and mallampati 3 the
patient was anesthetized and intubated successfully with the second attempt
using stylate and applying cricoid pressure in the middle of procedure saturation
decrease from 95 to 80%. The anesthetist notice gastric content in the mouth
area and bilateral crepitation on auscultation and suspect aspiration of gastric
content into the lung.
16. Manage this patient following appropriate steps of aspiration
management
Required resource
Emergency drug(adrenalin)
Monitors (BP apparatus, stethoscope and pulse oxymetry)
GA equipment's(oxygen source, laryngoscope, ETT, IV anesthetic drugs,
suction machine, suction tube, stylate, airway mask)
17. Management and treatment for aspiration
If aspiration occurs, treatment is symptomatic.
Call for help
Place the patient to head down and lateral position
Inspect the airway and remove particulate matter
Remove the airway suction the pharynx
Intubate and suction bronchial tree when the airway secured
Ventilate with 100% O2
Began PEEP as necessary to maintain oxygen saturation
Administer B2 agonist
18. Continued…
• Auscultate breath sounds periodically for wheezing, rhonchi, and rales
• Obtain initial chest radiograph
• Consult bronchoscopy
• Administer corticosteroids for edema and inflammation
• Place NG tube and empty stomach before extubation
• Perform smooth extubation
• Document the intraop period event
• Transfer to PACU/ICU
• Inform the recovery personnel about patient